Amyloid fibril protein in familial amyloid polyneuropathy.

Amyloid fibril protein was purified from organs of patients with familial amyloid polyneuropathy (Nagano prefecture, Japan). When compared with amyloid fibril protein from primary amyloidosis and secondary amyloidosis, the protein from familial amyloid polyneuropathy was shown to differ in the molecular weight of the subunit. This protein subunit had the same molecular weight as the prealbumin subunit, but had a different amino acid composition: It did not contain tryptophan and cysteine. Amyloid fibril protein from familial amyloid polyneuropathy therefore differed from IgG, AA protein, and prealbumin.